Use a resource throttle to implement shouldOverrideUrlLoading.

android_webview/java/src/org/chromium/android_webview/AwContents.java

Index: android_webview/java/src/org/chromium/android_webview/AwContents.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index d24cb7cbeccd81287981368ba41df25e6c645c9f..a3cdca94ddcd391ceb6a2a79b8236ecff7d130fe 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -472,19 +472,38 @@ public class AwContents implements SmartClipProvider,
         @Override
         public boolean shouldIgnoreNavigation(NavigationParams navigationParams) {
             final String url = navigationParams.url;
+
+            final int transitionType = navigationParams.pageTransitionType;
+            final boolean isLoadUrl =
+                    (transitionType & PageTransition.FROM_API) != 0;
+            final boolean isBackForward =
+                    (transitionType & PageTransition.FORWARD_BACK) != 0;
+            final boolean isReload =
+                    (transitionType & PageTransition.CORE_MASK) == PageTransition.RELOAD;
+            final boolean isRedirect = navigationParams.isRedirect;
+
             boolean ignoreNavigation = false;
-            if (mDeferredShouldOverrideUrlLoadingIsPendingForPopup) {
-                mDeferredShouldOverrideUrlLoadingIsPendingForPopup = false;
-                // If this is used for all navigations in future, cases for application initiated
-                // load, redirect and backforward should also be filtered out.
-                if (!navigationParams.isPost) {
-                    ignoreNavigation = mContentsClient.shouldOverrideUrlLoading(url);
-                }
+            // Any navigation from loadUrl, goBack/Forward, or reload, are considered application
+            // initiated and hence will not yield a shouldOverrideUrlLoading() callback.
+            if ((!isLoadUrl || isRedirect)
+                    && !isBackForward
+                    && !navigationParams.isPost) {
+                ignoreNavigation = mContentsClient.shouldOverrideUrlLoading(url);
             }
+
             // The shouldOverrideUrlLoading call might have resulted in posting messages to the
             // UI thread. Using sendMessage here (instead of calling onPageStarted directly)
             // will allow those to run in order.
-            if (!ignoreNavigation) {
+            if (isRedirect) {
+                mContentsClient.getCallbackHelper().postOnPageStarted(url);
+                // We can post onPageFinished here since we know that the navigation will fail.
+                // Also AwWebContentsObserver.didFail does not call OnPageFinished when the
+                // navigation is overridden because we don't want an onPageFinished for such a
+                // navigation unless it is a redirect.
+                if (ignoreNavigation) {
+                    mContentsClient.getCallbackHelper().postOnPageFinished(url);
+                }
+            } else if (!ignoreNavigation) {
                 mContentsClient.getCallbackHelper().postOnPageStarted(url);
             }
             return ignoreNavigation;